IThumbnailCache::GetThumbnail method (thumbcache.h)
Gets a cached thumbnail for a given Shell item.
Syntax
HRESULT GetThumbnail(
[in] IShellItem *pShellItem,
[in] UINT cxyRequestedThumbSize,
[in] WTS_FLAGS flags,
[out, optional] ISharedBitmap **ppvThumb,
[out, optional] WTS_CACHEFLAGS *pOutFlags,
[out, optional] WTS_THUMBNAILID *pThumbnailID
);
Parameters
[in] pShellItem
Type: IShellItem*
A pointer to the Shell item for which to retrieve a thumbnail.
[in] cxyRequestedThumbSize
Type: UINT
The requested thumbnail size in pixels. The maximum value is 1024.
[in] flags
Type: WTS_FLAGS
A combination of values from the WTS_FLAGS enumeration. See the Remarks section for rules and a list of possible combinations.
[out, optional] ppvThumb
Type: ISharedBitmap**
The address of an ISharedBitmap pointer that, when this method returns successfully, receives the object used to access the thumbnail. This parameter may be NULL.
[out, optional] pOutFlags
Type: WTS_CACHEFLAGS*
A pointer to a value that, when this method returns successfully, receives a combination of the following flags from the WTS_CACHEFLAGS enumeration.
WTS_DEFAULT (0x00000000)
0x00000000.
WTS_LOWQUALITY (0x00000001)
0x00000001. Set when the returned bitmap dimensions are less than cxyRequestedThumbSize.
WTS_CACHED (0x00000002)
0x00000002. Set when the returned image is in the cache.
[out, optional] pThumbnailID
Type: WTS_THUMBNAILID*
A pointer to a value that, when this method returns successfully, receives a unique ID for the returned thumbnail. This parameter may be NULL, in which case the thumbnail ID is discarded.
Return value
Type: HRESULT
Returns S_OK if successful or a standard COM error value otherwise, including the following:
Return code | Description |
---|---|
|
A parameter is invalid. |
|
The Shell item does not support thumbnail extraction. For example, .exe or .lnk items. |
|
The extraction took longer than the maximum allowable time. The extraction was not completed. |
|
A surrogate process was not available to be used for the extraction process. |
|
The WTS_FASTEXTRACT flag was set, but fast extraction is not available. |
Remarks
If a thumbnail is extracted, it will be cached unless WTS_EXTRACTDONOTCACHE is specified.
The following combinations are valid for the flags parameter.
WTS_INCACHEONLY |
WTS_FASTEXTRACT |
WTS_EXTRACT |
WTS_EXTRACT | WTS_SLOWRECLAIM |
WTS_FORCEEXTRACTION |
WTS_FORCEEXTRACTION | WTS_SLOWRECLAIM |
WTS_EXTRACTDONOTCACHE |
GetImage also uses this cache and can provide an easier way to retrieve the thumbnail. However, GetImage is more general and will retrieve an icon as a fallback.
Requirements
Requirement | Value |
---|---|
Minimum supported client | Windows Vista [desktop apps only] |
Minimum supported server | Windows Server 2008 [desktop apps only] |
Target Platform | Windows |
Header | thumbcache.h |
See also
Σχόλια
https://aka.ms/ContentUserFeedback.
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